The recent rapid changeover to plastics in the field of spectacle and camera lenses gave impetus to the development of plastic lenses such as those of polymethyl methacrylate, polycarbonate, diethylene glycol bisallylcarbonate, etc., which are already in use, and the following and other plastic lenses excellent in clarity, impact resistance and refractive index.
For example, Japanese Kokai Tokkyo Koho No. 56-166214 (Japanese Patent Publication No. 58-14449) describes a method for producing a flame-resistant lens of high refractive index which comprises copolymerizing a dimethacrylate or diacrylate compound in which a halogen-substituted aromatic ring is bound to a methacroyloxy or acroyloxy group through an alkylene glycol group with an aromatic ring-containing radically polymerizable monofunctional monomer in the presence of a radical polymerization initiator.
Japanese Kokai Tokkyo Koho No. 57-136602 discloses a plastic lens of urethane resin type having a refractive index of 1.45-1.70 and an Abbe number of 35.about.60 which is based on an urethane resin produced by addition polymerization of a reaction product between an isocyanate compound and an OH-containing unsaturated compound.
Japanese Kokai Tokkyo Koho No. 59-87126 discloses a process for manufacture of a lens from a composition comprising an epoxy(meth)acrylate obtainable by reacting an epoxy resin, which is obtainable by condensation between bisphenol A and/or bisphenol F and epichlorohydrin, with (meth)acrylic acid, a compound containing two or more allyl or allylidene groups per molecule, a compound containing two or more mercapto groups per molecule and a radical polymerization initiator.
Japanese Kokai Tokkyo Koho No. 59-87127 describes a process for manufacture of a lens which comprises blending said epoxy[meth)acrylate with a vinyl monomer, pouring the resulting curable composition in a casting mold and curing the same with actinic radiation. Japanese Kokai Tokkyo Koho No. 59-87128 describes a process for manufacture of a lens which comprises pouring a curable composition prepared by mixing said epoxy(meth)acrylate with an aliphatic polyhydric alcohol (meth)acrylate ester into a casting mold and curing the same with actinic radiation. Furthermore, Japanese Kokai Tokkyo Koho No. 59-87129 describes a process for manufacture of a lens which comprises pouring said epoxy(meth)acrylate in a casting mold and curing it with actinic radiation.
Japanese Kokai Tokkyo Koho No. 60-103301 discloses a resin material for high refractive lenses which is a copolymer between a tetrahalobisphenol A diallyl carbonate-(meth)acrylic acid adduct and a monofunctional monomer.
Japanese Kokai Tokkyo Koho No. 61-200501 describes a process for manufacture of a plastic lens in which a reactive mixture or reaction intermediate comprising a tetrabromobisphenol-alkylene oxide adduct, a hydroxyalkyl (meth)acrylate and a non-yellowing aromatic ring-containing polyisocyanate is poured in a casting mold and cured in situ.
Japanese Kokai Tokkyo Koho No. 62-73201 discloses a plastic lens of high refractive index as produced by vinyl polymerization of an urethanated (meth)acryl monomer obtainable by reacting a 2,2-bisphenolsulfone (bisphenol S) derivative monohydroxymono(meth)acrylate with a polyfunctional isocyanate.
However, these known optical lenses are not fully satisfactory in all the performance and cost requirements, inclusive of clarity, refractive index, Abbe number and impact resistance. Furthermore, the availability of any other suitable optical resin would broaden the choice and enable the industry to meet ever more sophisticated market demands.
The object of the invention is to provide an optical resin product meeting the above-mentioned requirements in good balance with an economic advantage.